The present invention relates to a height adjustable supporting device for an instrument, more particularly an ophthalmological instrument, whereby the weight of the instrument and of the height adjustable parts of the supporting device are compensated by spring force. Known devices of this kind are provided with a compensating spring which is adjusted to a determined weight (U.S. Pat. No. 3,463,579). However, the weight to compensate is in many cases not given one for all in that either instruments of different types are used or in that instruments with a determined basic execution may be combined with different accessories. As an example, the microscope of a slit lamp can be completed with different accessories, e.g. a tonometer, a changer of stereo angle, a beam splitter, a secondary viewing tube and other aggregates. However, a unique compensating spring can compensate satisfactorily only a determined weight and a bad weight, compensation renders more difficult the vertical adjustment of the supporting device, resp. of the instrument supported by it.